5  Habitat Compression Index

cciea_yr <- 2024
ds_id <- 'cciea_OC_HCI'    
ts_id_list = list('cciea_OC_HCI1', 'cciea_OC_HCI2', 'cciea_OC_HCI3', 'cciea_OC_HCI4')


# Source some local code
source("script_region.R")

Description The Habitat Compression Index (HCI) is the area of cool habitat along the coast, which is suitable for a diverse and productive portion of the CCE food web. HCI is estimated in four biogeographic provinces along the shelf within the CCE.

Metafile name /home/isaac/Work/IEA/2024/tech_document/CCIEA_metadata_2024-09-26.xlsx

Indicator Category Climate and Ocean Drivers

Data Steward Schroeder

Erddap Dataset ID cciea_OC_HCI

CCIEA timeseries ID cciea_OC_HCI1, cciea_OC_HCI2, cciea_OC_HCI3, cciea_OC_HCI4

Region NCC (43.5-48.0N), CCC (40.0-43.5N), CCC (35.5-40.0N), SCC (30.0-35.5N)

Public availability statement Source data are publicly available.

Data sources Surface temperature data are the 2 m temperature levels of the University of California Santa Cruz 31-year historical reanalysis (https://oceanmodeling.ucsc.edu/reanalccs31/) and near-real-time (NRT; https://oceanmodeling.ucsc.edu/ccsnrt/) data-assimilative models.

Additional Information The HCI is defined over 4 regions along the coast (43.5-48°N, 40-43.5°N, 35.5-40°N, and 30-35.5°N). The HCI is calculated the same for each region and is defined as the area of cool monthly averaged sea temperatures at a depth of 2 m that fall below a temperature threshold, in a region extending from the coast to 150 km offshore between the latitude ranges of the 4 regions. Each month has a unique temperature threshold that is defined as the spatial average of all 2 m temperatures from the coast to 75 km offshore in the latitudinal region for a given month over a climatological period of 1980 to 2010 Schroeder et al. (2022).

Figures

(a) Region 1 (43.5-48°N)

 

(b) Region 2 (40-43.5°N)

(c) Region 3 (35.5-40°N)

 

(d) Region 4 (30-35.5°N)

Figure 5.1: Monthly habitat compression index (HCI) for January 1980 to November (2024). The index describes the contraction and expansion of cool shelf habitat between the latitude range and from the coast out to 150 km offshore. Each month the area of water below a temperature threshold is calculated where a value of 0 represents no cool water in the region and a value of 1 indicates the whole area is comprised of cool water. Monthly resolved temperature thresholds are the spatial mean of temperature values between the latitude range and from the coast out to 75 km offshore over a climatological time period of 1980-2010.

(a) Region 1 (43.5-48°N)

 

(b) Region 2 (40-43.5°N)

(c) Region 3 (35.5-40°N)

 

(d) Region 4 (30-35.5°N)

Figure 5.2: Seasonal averages of HCI.

2024 Conditions

• For regions 1-3, the HCI during Winter 2024 (Figure 5.1, Figure 5.2) was zero due to the 2023-24 El Niño influence on the CCS (Figure 1.2 (a)).
• The influence of 2023-24 El Niño was not as great for the HCI in region 4 (Figure 5.2 (d)).
• Spring 2024 HCI values average (Figure 5.2).

References

Santora, Jarrod A, Nathan J Mantua, Isaac D Schroeder, John C Field, Elliott L Hazen, Steven J Bograd, William J Sydeman, et al. 2020. “Habitat Compression and Ecosystem Shifts as Potential Links Between Marine Heatwave and Record Whale Entanglements.” Nature Communications 11 (1): 1–12.

Schroeder, Isaac D., Jarrod A. Santora, Nate Mantua, John C. Field, Brian K. Wells, Elliott L. Hazen, Michael Jacox, and Steven J. Bograd. 2022. “Habitat Compression Indices for Monitoring Ocean Conditions and Ecosystem Impacts Within Coastal Upwelling Systems.” Ecological Indicators 144 (November): 109520. https://doi.org/10.1016/j.ecolind.2022.109520.